Projectile fuze for a gun with a rifled bore



June 19, 1962 R. SIMMEN 3,039,392

PROJECTILE FUZE FOR A GUN WITH A RIFLED BQRE Filed July 20, 1959 4 Sheets-Sheet 1 June 19, 1962 R. SIMMEN 3, 3

PROJECTILE FUZE FOR A GUN WITH A RIFLED BORE Filed July 20, 1959 4 Sheets-Sheet 2 /V MEN 7 E055 e7- 5/MM :N

R. SIMMEN 3,039,392

June 19, 1962 PROJECTILE FUZE FOR A GUN WITH A RIFLED BORE 4 SheetsSheet 3 Filed July 20, 1959 /NV.NTOQ 5055 127 SIM/W EN June 19, 1962 R. SIMMEN 3,03

PROJECTILE FUZE FOR A GUN WITH A RIFLED BORE Filed July 20, 1959 4 Sheets-Sheet 4 whom r012 3,fi3,392 Patented June .19, 1962 PROJECTILE FUZE FOR A GUN WITH A RIFLED BORE Robert Simmer], Geneva, Switzerland, assiguor to Mefina S.A., Frihourg, Switzerland, a' corporation of Switzerland Filed July 20, 1959, Ser. No. 828,137 Claims priority, application Switzerland July 25, 1958 I 2 Claims. (Cl. 102-71) The present invention has for its subject a projectile fuze for use in a gun with a rifled bore. The fuze is of the type comprising safety devices for transport and combined trajectory and primer safety means, wherein the primer is carried by a movable support maintaining it spaced from its armed position during a predetermined period of time. Fuzes of this general type also include an automatic destruction device released by a spring and controlled by a timing device; a percussion device with mechanical retardation means comprising a pusher the axial position of which controls, by means of a bolt, the locking and release respectively, of a spring loaded striker. The pusher member referred to is adapted to be displaced by an impact rod or by an automatic destruction device.

Projectile fuzes of the type indicated above are known, wherein the automatic destruction device comes into operation by reason of the diminution of the rotation of the projectile towards the end ofits trajectory. These fuzes have the disadvantage of having a large variation in the time period of auto-destruction.

The primary object of the present invention is to overcome this disadvantage by providing a projectile fuze wherein a single clockwise mechanism controls both the automatic destruction device as well as the combined'trajectory and primer safety device, so that an exact timing of the period of automatic destruction may be obtained and thus assure that the fuze will not be set in armed position until after it is a safe distance from the gun from which it is fired.

One form of construction of the fuze forming the subject of the invention is shown diagrammatically and by way of example in the accompanying drawings, Where- FIG. 1 is a general axial section of the fuze.

FIG. 2 is a cross-section on the line II'II of FIG 1.

FIG. 3 is a cross-section onthe line IIIIlI of FIG 1.

FIG. 4 is a section on the line IVIV of FIG. 1.

FIG. 5 is a view similar to FIG. 1, showing the fuze in the percussion position by impact.

FIG. 6 is a view similar to the preceding one, showing the fuze in the percussion position by auto-destruction.

This fuze comprises a body 1 adapted to be mounted in an ogival head 2 of the projectile. Said body 1 is normally constituted by a series of plates piled on one another and formed in such a manner as to contain the difierent movable members which the fuzecomprises. For simplifying the drawing and the description, the body 1 of the fuze shown is assumed to be in two principal parts.

The point of the body 1 is hollow, in such a manner as to receive a percussion rod 3 protected in the normal position of the fuze, by a plate 4.

The firing of the projectile is eifected through the medium of a striker 5 of which the point 6 is adapted to perforate a primer 7 carried by a movable support 8 lodged in .the lower part of the body 1. The flame produced by the percussion of the primer 7 is adapted to provoke the firing of the detonator 9 through the medium of a transmission charge 10.

A first mechanism is provided for provoking a mechanical retardation between the moment at which an impact is produced on the rod 3 and the moment at which there is produced the percussion of the primer 7 by the point 6 of the striker '5. As will be seen in FIG. 1, the striker 5 is loaded by a spring 11. In fact, said striker 5 has a collar 12 and the spring 11, engaged around the rod of the striker, tends to push this into the percussionvposb tion of the primer 7. However, the striker 5 is retained in its normal position by a bolt 13, constituted, in the example shown, by a ball. The position of said bolt 13 is controlled by a pusher 14 capable of being moved axially parallel to the geometrical axis of the fuze. This pusher 14 has a recessed part 15 enabling the bolt 13 to release the collar 12 and thus the striker '5 when the said recess 15 is opposite the seating 16 in which the bolt 13 is disposed. The axial movement of the pusher 14 is adapted to be provoked by the percussion rod 3- which is in contact with one of the ends of the said pusher 14. As will be understood from the foregoing description, the movements to which the parts 13 and 14 are to be subjected .for passing from their rest position, shown in FIG. 1, to their percussion position, shown in FIG. 5, necessarily requires a predetermined period of time, in view of the inertia and friction which must be overcome for moving said parts 13 and 14 allowing of the release of the striker 5.

Said fuze also comprises an automatic destruction device adapted to provoke the explosion of the projectile towards the end of its trajectory, particularly when the projectile has not reached its target. This automatic destruction device is controlled from a sleeve 17 disposed around the percussion rod 3. Said sleeve 17 is loaded by a spring 18 located between said sleeve and the percussion rod 3, said spring 18 bearing against a shoulder 19 of the body 1 of the fuze. The automatic destruction of the projectile should therefore take place from said sleeve 17 and through the medium of said striker 5, thus through the same parts 13 and 14, utilised for the percussion by impact on the rod 3. However, this automatic destruction device is controlled by a clockwork comprising essentially a driving sector 20 pivoting about an axis 21. This driving sector 20' constitutes to some extent an activating member which, under the action of centrifugal force, comprises the motive force for driving the clockwork. In fact, the shape of this driving sector 20 and the position of its pivotal axis 21 (see FIG. 2), causes, when the projectile is driven in rotation about itself, the resultant centrifugal force to tend to produce a displacement of the driving sector 20 in the direction of the arrow 22 in FIG. 2. The move ment of the driving sector 2% from its normal position, shown in full lines in FIG. 2, to its final position shown in broken lines, is controlled by the gear trains formed by the pinion 23, gearing with the driving sector 20, said pinion 23 being secured to a toothed wheel 24 itself gearing with a pinion 25 secured to a toothed wheel 26 which drives a pinion 27 secured to a wheel 23 gearing with a pinion 29 secured to an escape wheel 30. The movement of said escape wheel 30 is controlled by a pallet fork 31 forming part of a rocking member 32.

The action of the clockwork on the auto-destruction device is effected through the medium of a slide 33 guided by the pusher 14. In fact, said pusher 14 is tubular and the slide 33 is constituted by a rod sliding in the interior of the pusher 14. The end 34 of said slide 33 bears against the driving sector 20 in the position of rest. The other end 35 of said slide is subjected to the action of the sleeve 17 loaded by the spring 18. Thus the automatic destruction device can only function when the driving sector 2%} has released the end 34 of the slide 33 after having accomplished its complete angular movement (see position shown in broken lines in FIG. 2, as also FIG. 6).

I armed position.

The 'fuze also provided witha combined: safety tra- I 'je'ctory' and primer. I In fact, and as already indicated 'above', the prirner l is carried by aarnovahle support 8.

stable manner in the armed position by reason ofa'lock- 'ing member instituted by .a piston 331slidingina b re a bore 47 provided radially in the body 3 of the fnze. This piston 46 is subjected to the action of a spring 48 which urges it towards the interior of the fuze in such a manner that the point 49 of this engages in a bore 50 of the movable support 8 and maintains this in the unarmed position of rest. Under the action of centrifugal force, after the projectile has passed out of the gun, the piston 46 is thrust radially towards the exterior and releases the movable support 8 from the primer 7.

A safety device locks the balance device 32 at rest. As shown in FIGS. 1 and 3, said safety device cornprises a slide 51 capable of sliding in a recess 52 provided radially in the body 1. Said slide 51 carries a pin 53 for locking the balance device 32. The slide 51 is maintained in the locking position, when at rest, by a spring 54 of the clamping spring type mounted in a groove of the body 1. Under the action of centrifugal force, when the projectile has left the mouth of the gun, the slide 51 withdraws radially from the axis of the fuze and releases the pallet fork 31.

A double safety device locks the pusher 14 in the position of rest. This latter safety device comprises a locking slide 55 sliding in a radial groove 56 of the body 1. The inner end 57 of this slide 55 is in the form of a fork and engages under the pusher 14 whilst passing on opposite sides of the rod or slide 33. Said slide 55, which is sensitive to centrifugal force, is maintained in the locked position by a body 58 in the form of a piston 59 with an enlarged end. This enlarged end 58 engages in a recess 60 of the slide 55. Said body 58in the form of a piston is mounted in such a manner as to be capable of sliding in a cylinder 61 provided in the body 1 of the fuze parallel to the axis thereof. A spring 62 loads the body 58 and the effect of this loading of the spring 62 on the said body 58 is added to the force of inertia of this I This movable support 8 I is pivoted about an axis 36.: I I

The shape of'this movable support 8 is? such that, under 1 the action of centrifugal: force, it tends to turn in the I direction of. the arrow .37 so as to occupy: the position I 1 indicated in dotted lines in FIG. 4 when his in the armed I T position; I This I movable support :8 I is niaintaincd I in a I 39 of the said support '8 and which, under the action I I I i of centrifugal force, projects a predetermined lengthfrom the bore 39am becomes locked in a notch I46 in the I body of thefuze when the movable SuppQrt S' is in the I However, the movement of this move able support S from its rest position indicated 'infull I I lines in FIG. 4 to itsarinecl position indicated by dotted I lines, is controlled by amernber tt itself controlled by I 2 i I one of the elements of the cinematic chain of the clocle I I i work mechanism, on the: occurrence of the: wheel 26 I I i 1 i I which carries a pin 4-2. in the example illustrated, said I I l i 1 I I member '41 is constituted by a lever with two arms 43 I 3 and '44 pivoting about a spindle I arranged I parallel I I to the axis of the fuzei The arm 44 ed-opera'te's with i 1 j the movable-support 8- of the primer 7, whilst the other I I i I arm 43 co-operates=withthe pin'42 carried bythewheel II 26 of the cinematic chain of the clockwork. Thus the I I I j r no'vablei support of the primer l' cannot move towards r I I its set position until after the 'pin' 42 has: released} the I arm 43, which occurs after the clockwork mechanism I i i :has functioned during} a predetermined I period of time; s i I 'Said' fit-z e comprises a plurality of safety devices for i I I I .transport,adapted tolock its principal m'emhers for main- I I taining them in the rest position in spite :of the shocks which 'rnay inte rvene during the course of manipulation. II

and of transport of the projectile. 'A first safet'y device 3 I is provided for maintaining the movable support 3 :in' I the non-armed position; 'As' wines seen inFIG; 4, this I I safety device comprises a piston'dd capable of sliding'in body due to. the: accelerationofzthe projectile in the. gun I I I during the firing.- This :double security: thus permits of I guaranteeing that the :pusher 14 is not release as l ng.

as the projectile has not leftthemuzzleof thegun I It, I I I I is to be observed that onfiring, the inertia of the pushei' I 14 itself, which bears stronglyonthe extremity57 of the slide '55, alsoparticipates in: the locking of, thislatter, I I whilst preventing it from thrusting itself radially under s I the action of centrifugal force,.whilst the axial accelcra .tion of .the projectile makes itself felt. I I I I I I I As will be seen from the-drawings, all the dilferent se c I curities which have: been described are located in, the. I vicinity of the j periphery: of the :fuze andthe' openings: I I

63,64; and65 provided in thisbody 1, permit of verify ingtheir position during the mounting of the fuze. inthe projectile. I I I I I The operation of the fuze; described hereinhefore .isas

follows:

. I In. the normal position, the. different members. of this I fuzeoccupy the position shown-in FIG. ;1- and inFIGS; '2, 3: and 4 (position indicated in full lines). I 1 I I On. firing of the Projectile. underthe effect; of

safety I device is pushed. towards the front .by the slide :55 whichis thrust radially outwardly-under the actionof I I centrifugal force, by lifting said body I58: against .the aetionof the spring 62. Simultaneously, the piston 46 is r I thrust radially in the same way as the slide ISZL Thus I I thebalance device or rocking member 32 isreleased and i I I as the driving. sector 20 is, also subjected to centrifugal r I .force, it; entrains the entire clockwork mechanism 23; to I 32 inmovement. I

position'in which his maintained by the piston 38 (see FIG. 4, position indicated in dotted lines). The position of the pin 42 on the wheel 26 is selected in such a manner that the fuze cannot be set into the armed position until after a predetermined period of time constituting in fact the gun and cover security of the fuze. This security may reach an order of magnitude of meters on the trajectory of the projectile.

When the projectile meets an obstacle in the course of its trajectory, the plate 4 is forced inwardly and the percussion rod 3 is urged towards the rear. This rod 3 also forces the pusher 14 rearwardly in such a manner that the recess 15 is brought opposite the seating 16, which enables the ball 13 to escape into this recess 15 and to release the collar 12 and thus the striker 5. Under the action of the spring 11, this sets off the primer 7 of which the flame provokes, through the medium of the transmission charge or relay 10 and the detonator 9, the explosion of the charge of powder in the projectile.

The time which elapses between the driving in of the plate 4 and the ignition of the primer 7 by the striker 5 enables the projectile to pass completely through the obstacle, constituted, for example, by the wall of an aircraft wing, before the deflagration of the shell takes place. For this reason this deflagration takes place effectively in the interior of the aircraft wing, thus damaging this much more seriously than if the explosion had been produced by impact against the external wall of the wing.

In the case when the projectile does not meet any obstacle in its trajectory, the driving sector 20 continues its angular movement until it reaches the position indicated in broken lines in FIG. 2. At this moment the slide 33, which "bears with friction by its end 34- on the upper part of the sector 20, is freed axially. The release of the slide 33 then allows the sleeve 17 of the autoa very I strong axial acceleration towhich the projecti le; is;sub;- jected in the firing muzzle, all the dilferent members of: I gtheifuzeremain blocked, eventhosesensitiveto centrifu I gal force. When the axial accelerationceases, afterthe; I projectile has left the gun, the; body- 58. of the double destruction device to be repelled by the spring 18, against the pusher 14 of which the notch 15 is brought opposite the seating 16 of the ball 13. For this reason, the striker 5 is released and provokes the ignition of the primer 7. Thus the destruction of the projectile may take place before it falls to the ground in the case of a projectile of an anti-aircraft gun.

The variation of the auto-destruction periods is very slight with an automatic destruction device of the type described above, by reason of the fact that this is practically independent of a diminution of the rotation of the projectile but depends solely upon the function of a clockwork mechanism.

It is possible to imagine numerous variations in construction of the fuze above described. Thus the slide 33, instead of being guided by the pusher 14, may be guided independently thereof in a bore provided for this purpose in the body 1 of the fuze. Further, the member 41, instead of being constituted by a lever with two arms, may also be constituted by a slide controlled by any element of the cinematic chain of the clockwork mechanism and controlling the movement of the movable support 8 of the primer 7 towards its armed position.

It will be understood that the number of wheels of the clockwork and the disposition thereof relatively one to another in the body of the fuze, may be selected in any suitable manner.

As regards the different safety devices for transport, as shown, these may be replaced by any other safety device sensitive to centrifugal force or to axial acceleration, of known construction.

I claim:

1. In a projectile fuze for use in a gun with a rifled bore said fuze including safety locking means for preventing detonation of said projectile during transport, the combination comprising a fuze body, an axially slidable percussion rod positioned within said body adjacent the point thereof, a spring-loaded striker also within said body and located below said percussion rod and out of axial alignment therewith, a primer carried by a movable support lying beneath said striker, a detonator beneath said primer, retardation means intermediate said percussion rod and said striker for delaying percussion of said primer upon impact of said fuze with an objective, said retardation means including an axially movable hollow shaft having a peripheral recess therein, the upper end of said shaft engaging said percussion rod, bolt means normally engaging said shaft and said striker to retain the latter in inoperative position, said striker moving to operative position when said shaft is driven inwardly by said percussion rod permitting the bolt means to enter the peripheral recess on said shaft thereby releasing said striker, autodestruction means adapted to cause the explosion of the projectile towards the end of its trajectory when said projectile has missed its target, said auto-destruction means including a sleeve surrounding said percussion rod, spring means between said percussion rod and said sleeve and normally urging said sleeve downwardly, timing means controlling said auto-destruction means, said timing means including a rotatable driving sector actuated by the centrifugal force created by the rotation of the projectile, slide means comprising a rod axially slidable within said hollow shaft, the upper end of said rod engaging the lower end of said sleeve and the lower end of said rod engaging said driving sector whereby when said sector completes its rotative cycle, the lower end of said slidable rod is freed to move axially downwardly permitting said sleeve to strike the hollow shaft to move it downwardly thereby causing the bolt means to enter the peripheral groove on said shaft; release the striker; and ignite said primer, combined trajectory and primer safety means controlling movement of said movable support from rest position to armed position, said last mentioned means including a member controlled by said timing means, the simultaneous control of both said auto-destruction means and said combined trajectory and primer safety means by said timing means assuring accuracy in arming of said fuze and preventing premature detonation thereof.

2. A projectile fuze according to claim 1, wherein the member of the combined trajectory and primer safety means which is controlled by the timing means comprises a lever having a pair of spaced apart arms, said lever pivotally mounted in said fuze body on an axis parallel to the axis of the fuze, one of said arms engaging said movable support and the other of said arms engaging an element of said timing means.

References Cited in the file of this patent UNITED STATES PATENTS 1,863,888 Varaud i June 21, 1932 2,449,170 MacLean Sept. 14, 1948 2,457,254 'McCaslin Dec. 28, 1948 2,537,855 'Porter Jan. 9, 1951 2,825,284 Kuhn 'Mar. 4, 1958 FOREIGN PATENTS 297,451 Switzerland June 1, 1954 

